As magnetic recording films to constitute hard disks and the like mounted on computers, etc., CoPt-based thin films have been used in the past, and increase of recording density has been achieved by a perpendicular magnetic recording system. In recent years, however, a demand for increase of recording density has been strengthened more and more, and it has become difficult for the CoPt-based thin films to meet the demand.
Then, as magnetic recording films of the next generation that substitute for the CoPt-based thins films, FePt-based thin films have been proposed. The FePt-based thin films have an advantage of higher magnetic anisotropy as compared with the CoPt-based thin films. On the other hand, the FePt-based thin films have a disadvantage that because the particles constituting the thin films become excessively large, the structures of the thin films become disordered to thereby lower magnetic properties.
On this account, techniques to control the magnetic properties by adding carbon or the like to the FePt-based thin films have been studied.
In Japanese Patent No. 3,950,838, a technique of sputtering Fe sputtering target, Pt sputtering target and C sputtering target at the same time to obtain a FePtC-based magnetic recording film having excellent magnetic properties has been disclosed.
In this technique, however, there is a problem such that because three-element simultaneous sputtering using three kinds of sputtering targets is carried out, three or more cathodes for placing the sputtering targets thereon are required, and a large-scale apparatus becomes necessary.
This problem can be solved by preparing a sputtering target containing all the elements that constitute a magnetic recording film, such as Fe, Pt and C. If this sputtering target is used, it is enough just to sputter one sputtering target, and therefore, plural cathodes for placing sputtering targets become unnecessary. Hence, a FePtC-based magnetic recording film can be obtained without requiring a large-scale apparatus.
However, if carbon is contained in the sputtering target in a high concentration, it becomes difficult to increase the density of the sputtering target. If the density of the sputtering target is low, there occurs a problem that when the sputtering target is placed in a vacuum atmosphere in the sputtering process, the amount of a gas emitted from the sputtering target is increased, and the properties of a thin film formed by the sputtering are lowered.
The present invention has been made in order to solve the above problem, and it is an object of the present invention to provide a sputtering target which has high density even if it contains carbon in a high concentration and which is capable of providing a FePtC-based magnetic recording film of high performance.